The pancaking explanation. This has it that the floor joints on one floor were softened/damaged, which lets the floor collapse onto the one below. Their combined weight makes both floors collapse onto the one below, its joints then fail due to he weight and all three collapse and so on.
So when NIST states that Tower 7 collapsed in free fall, they eliminate this hypothesis. A free fall collapse has no resistance from the floors below, instead it requires the floor joints on all floors on all pillars to fail within 1/10th of a second. So nice though the pancaking hypothesis is, it doesn't match the evidence. And has been demonstrated, all 3 towers fell in free fall.
And the tower with the antenna? The one where the floors above (a) fall off at an angle and (b) had already immolated themselves from the bottom before reaching the tower below the crash site? What exactly is causing the tower below the crash site to pancake in a nice symmetrical pattern when (a) the crush load above is asymmetrical and (b) the crush load is spreading itself outwards not downwards.
And melting steel vs softening? OK I can buy that. Except that every floor gives way at the same time as the towers drop in free fall with no resistance from non-failed floors. And that there patently is molten steel - rivers of the stuff filmed flooding from the building, sitting there still molten days after the collapse according to fire crews, engineers on site and the themographic images.
I can buy the "steel just needed to be softened so don't worry about the temperature differential between jet fuel and steel melt" argument if it wasn't for the fact that (a) the steel was melted and (b) jet fuel and office furniture doesn't burn hot enough to melt it.
Something melted that steel into slag. Physics proves it wasn't fuel or furniture. The chemical evidence says thermite. I would be fascinated to hear a proper scientific rebuttal of this hypothesis that doesn't involve "duh, a plane hit the tower".
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